1. China

China accounted for 41 percent of the world's attack traffic
during the fourth quarter of last year, making the country the top source of
cyber assaults. China's share increased from 33 percent in the previous quarter
and 13 percent in the year-ago period, according to Akamai.

Investigations have
discovered a sophisticated hacker network in China. Some members are connected
to China's military, though the extent of these official operations is unknown. The government and its state-run media continue to deny China's
involvement in international hacking incidents.